Intersection Outlet Saturation Flow Rate (OSFR) Considering Game Behavior Within Intersection

Abstract

Most congestion occurs at intersections. Increasing the intersection capacity is crucial to alleviate the congestion. Saturation flow rate (SFR) is the basis for capacity calculation. SFR depends on many factors, and the guidelines sketched in the highway capacity manual can be applied. Most SFR are defined at the stop-line. The vehicles depart from the stop-line, enter the intersection, and exit from the outlet of the intersection. In a congestion scenario, vehicles would compete with each other before leaving the intersection and even get stuck within the intersection. The flow rate at the outlet thus decreased, and as a result, the theoretical capacity based on conventional SFR cannot be achieved. The manuscript defines a concept called OSFR (outlet saturation flow rate) to reflect the influence of the game behavior at the outlet and proposes a model that generates the OSFR. The model divides the vehicle’s movement into three parts: departure from the stop-line, drive along its trajectory, and finally exist from the outlet with game behavior with other drivers. A game model for outlet lane-choosing is proposed. Based on empirical data, the stop-line headway distribution model, speed model, and payoff function involved in the model were calibrated. The results show that the proposed model can generate real-world OSFR distributions. This model can effectively describe the invisible interaction between vehicles and can be used to get the outlet headway distribution in the case of mismatched lanes number.